Manufacture of steel



G. CINILLE.

MANUFACTURE OF STEEL- APPLICATION FILED AUG-10, 1910. RENEWEDIAN-30.1919.

1 352 58Q Patented Sept. 14, 1920.

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I UNITED STATES PATENT OFFICE..

GEORGES CINILLEOF EPIERRE, FRANCE.

MANUFACTURE OF STEEL.

To all whom it may concern Be it known that I, GEORGES CINILLE, acitizen of the Republic of France, residing at Epierre, Savoie, France,have invented certain new and useful Improvements in the Manufacture ofSteel, of which the following is a specification.

The purpose of this invention is to manufacture hard steel containing asubstantial proportion of carbon and to obtain this result by means ofone single operation, purifying the crude iron in a hot workingconverter, in the presence of basic slag; the mass of molten metal beingconstantly stirred by the blasts from twyers so that all parts of thismass will come in contact with the basic slag. In this mannerphosphorus, sulfur and other impurities the crude. iron might contain,are directly eliminated and yet the steel will keep the desiredproportion of carbon. This process of direct manufacture of hard steelfrom the crude iron does not require a subsequent carburization of themetal as is the case with present processes.

This result is obtained by treating the crude iron in a converter bymeans of an electric current, which permits the use of basic slag (withlime as the base) and brings about the hot working.

The treatment of the crude iron in the converter under these conditionscan be car ried out even though the mass of molten metal in same shouldbe of great thickness, inasmuch as the direction of the twyers resultsin stirring up the molten material and in bringing all its parts incontact with the basic slag which is rich in lime. This stirring is madepossible in a converter owing to the large space over the metal.

Through this invention special steels of given compositions can beproduced in one single operation, without having to resort, as is thecase with all other processes known,

first to the treatment of the crude iron in a Bessemer converter andthen to the treatment of the steel thus obtaineed in an electricfurnace.

This process is worked in a converter which is used not only as ametallurgical, but also as a heating device, as the electric currentfurnishes the necessary heat to entirely produce the chemical andthermic reactions required for the treatment of the most impure pigiron. It is essential to point out that the very close contact exist-Specification of Letters Patent. Patented Se t 14 1920 ApplicationliledAugust 10, 1910, Serial No. 576,561.

Renewed January 30, 1919. Serial No. 274,108.

ing between the stirred metal and the basic slag, together with the hightemperature de veloped insures the elimination of such impuritles assulfur, phosphorus, silicon and manganese, before the carbon is entirelyburnt out, a substantial proportion of it still remaining in the metal.

By means of this process a control of the temperature, the basicity andthe nature of the scoria is obtained, and it is a very easy matter tosecure a reducing atmosphere; consequently, all sulfur and phosphoruscan be eliminated in a state of calcium sulfid and phosphate of limebefore the carbon disappears entirely, a result that cannot be obtainedwith any of the Bessemer converters by the processes in use at thepresent time.

As a result of this process, a hard steel, absolutely pure, is directlyobtained in the Bessemer converter from a pig iron more impure thanthose generally treated in converters. It is therefore possible to treatin the converter, a blast or cupola furnace cast iron that is notsuificiently silicious to be put through the Bessemer acid process ornot sufficiently phosphorus to be put through the Thomas furnace.

Moreover, as there is but one single operation to perform for the directproduction of hard steel, the pouring ofi of the metal from the Bessemerconverter into an electric furnace is avoided and consequently the lossof metal and the chilling which invariably follows this pouringoperation, are eliminated.

The changes which it is found convenient to make in the converter entailonly a com paratively small expense, and yet the converter thus modifieddoes away with the necessity of employing costly mixers or spe-' cialfurnaces, since the improved converter becomes in effect, anelectrometallurgical furnace. V

The attached drawing shows, by way of illustration, how the process isworked Figure 1 is a cross section of a converter with bottom blowingwhich is shown lying horizontally for the electric heating.

electrodes of opposite polarities at the surace of the metal bath.

converter, on the side of nose 0. Inthe converters with side blowing(see Figs. 3 and 4), the openings B which areused for the passage ofcarbons Uare placed over Figs. 3 and 4),

the blast-box A.

The electrodes U hang from brackets, independent of the converter. Thesebrackets are provided with drums and ropes for handling these electrodesand for holding the junction boxes. They are lowered into the furnacethrough theopenings B, when the converter is .in a horizontal "position.As the operation takes place at all times on a bath of molten metal,there is no fear that the arc may break, as is a frequent occurrencewhen the fusion of solid pieces of scrap iron is made in electricfurnaces.

When the converter has bottom blowing twyers, (see Figs. 1 and 2) theblast fromthe twyers naturally determines the stirring of the moltenmetal and all arts of this molten metal come in contact with the basicslag used in the process.

When the converter has side blowing (see the twyers are at leastpartially directedfrom the blast box .A toward neutral agent, as thecase may with the the-bottom of the converter. Two groups of twyersf'areseen on these figures, one ofhorizontal twyers which blow the air overthe molten metal bath and another group of inclined twyers whichinjectthe blast into the mass, producing a stirring of the metal and placingall of its parts in contact basic slag. It is understood that thesetwyers can blow either airor gas which will actas a reducing,

require.-

These twyers can be placed parallel with each other or else infan-shape, moreor less spread out,- as is shown which is a cross sectionalong Fig. 4, that are both fan shaped and plunging, which makes apowerful mixing of the molten metal with. the peripheral slag at by Fig.5; this figure,

' the center" from top to bottom of the bath.

The angle formed by each twyer with the vertical axis may vary accordingto the of opposite polarities, placed over' oxidizing or I 7 line M M ofshows .by dotted lines the twyers- The electrodes U are placed behindthe lime silicate, calcium sulfid and lime phos-' capacity of theconverter; and so also the angle formed by the twyers with thehorizontal plane.

molecules of the bath are in contact with the blast which produces aperfect mixing, as also with the slag. While the mixing of the metalwith the slag, through the blast, is avoided in all side blowingconverters in existence, the opposite result is obtained here, as theblast acts at the same-time as oxidizer and as a mechanical means ofgetting a thorough mixing. 1

The. horizontal twyers which inject the air or gas over the bath may beplaced obliquely, as shown by cross section, Fi 6, which is a crosssection through N N, ig. 4, so as to impart a revolving motion, in the"inside of the converter, to the blown gas.

lowing manner:-A supply of crude iron from a blast or a cupola furnaceis poured into the converter, and either before or after pouring thecrude iron, the necessary quantity of lime for transforming all thesilicon, the sulfur and the phorphorus into phate, is placed in theconverter. The solid lime remains in suspension in the bath,

thus producin a pasty mixture, insufli,

ciently fluid. The converter is then placed in a horizontal position,the electrodes U are lowered to the surface of the bath and the electriccurrent is permitted to go through; in this manner a high temperature isobtained which results in giving the lime an extreme fluidity. Theelectric current is then shut ofl and the electrodes are raised in orderto take them out of the co nverter. After this operation, the openingsused for the passage .of the electrodes are closed by means of ,plugs;the converter is then. set up again and placed in position for theblowing which comes either from the side or from the bottom. The air orthe gas under pressure brought in through the twyers stirs up the moltenmetal, mixes the metallic bath with the lime and puts the metal incontact with the slag. During the blowing, the flame projecting from theconverter nozzle is not reddish as in the ordinary Bessemer operations.It is just at this period that the 'scorification of the SlllCOIl takesplace.

As the silicon disappears, the flame burns whiter and whiter. The carbonburns with the air injected by the twyers and the bath being very hotand'very fluid, carbon mon- I oxid is produced, without a violent rise,as is frequently the case in converters. v

In the new process the blowing is stopped as soon as the rise takes'place, the converter is placed again in a horizontal position, themolten metal is left to decantand the clean- The inclination. of theside, blast plunging twyers is such that all the 85 The operation iscarried out in the foling is done in an extracalcareous, hot andreducing medium, the atmosphere of the converter being filled withcarbon monoxid.

Owing to these three conditions, high temperature, thorough mixing ofthe blast oxidized bath with the extracalcareous slag, and reducingatmosphere, the sulfur, phosphorus, silicon and manganese are eliminatedin the form of lime silicate, calcium and manganese sulfid and limephosphate. These elements being eliminated before the carbon is entirelyburned out, the metal may be cast just as it is, if the test bar shouldshow the percentage of carbon desired.

lVhen the cleaning is over, care is taken to connect the current to theelectrodes, to make the necessary additions and to shut off the currentwhen the bath is hot enough and no more gas escapes which might come outof the mass.

In order to avoid the contact of the atmosphere with the bath, a lightcalcareous slag is formed which protects the metal from cooling off.After a certain amount of time has elapsed, a hot steel flows, which ishomogeneous and possesses all the properties of electric steel.

lVhat I claim is 1. A process for producing hard steel which consists inplacing crude iron in a Bessemer converter in the presence of basicslags, supplying additional heat thereto to maintain an increasedfluidity of the mass, and injecting gas into the mass below its surfacein such manner as to intimately mix the metal with the basic slagwhereby to completely eliminate the phosphorus, sulfur and otherimpurities from the mass.

2. A process for producing hard steel containing a substantialproportion of carbon which consists in placing crude iron in a Bessemerconverter in the presence of basic slags, supplying additional heatthereto to maintain an increased fluidity of the mass, and injecting gasinto the mass in such manner as to intimately mix the metal with thebasic slag, whereby to eliminate the excess of carbon, and produce asteel of the desired carbon content without subsequent carburization.

3. A process for producing hard steel which consists in placing crudeiron in a Bessemer converter in the presence of basic slags, supplyingby means of an electric current additional heat thereto to maintain anincreased fluidity of the mass, and injecting gas into the mass belowits surface in such manner as to intimately mix the metal with the basicslag whereby to completely eliminate the phosphorus, sulfur and otherimpurities from the mass.

4; A process for producing hard steel containing a substantialproportion of carbon which consists in placing crude iron in a Bessemerconverter in the presence of basic slags, supplying by means of anelectric current additional heat thereto to maintain an increasedfluidity of the mass, and injecting gas into the mass in such manner asto intimately mix the metal with the basic slag, whereby to eliminatethe excess of carbon, and produce a steel of the desired carbon contentwithout subsequent carburization.

5. A process for producing hard steel which consists in placing crudeiron in a Bessemer converter in the presence of basic slags, heating themass by means of electrodes of opposite polarities arranged over themass, withdrawing the electrodes, and injecting gas into the mass insuch manner as to intimately mix the metal with the basic metal wherebyto completely eliminatethe phosphorus, sulfur and other impurities fromthe mass.

6. A process for producing hard steel which consists in placing crudeiron in a Bessemer converter in the presence of basic slags, supplyingadditional heat thereto to maintain an increased fluidity of the mass,and injecting into the mass gas in jets which are inclined with relationto one another in such manner as to intimately mix the metal with thebasic slag whereby to completely eliminate the phosphorus, sulfur andother impurities from the mass.

7. A process for producing hard steel which consists in placing crudeiron in a Bessemer converter in the presence of basic slags, supplyingadditional heat thereto to maintain an increased fluidity of the mass,injecting gas into the mass below its surface in such manner as tointimately mix the metal with the basic slag, and injecting into theconverter gas over the mass of metal whereby to completely eliminate thephosphorous, sulfus and other impurities from the mass.

8. A process for producing hard steel which consists in placing crudeiron in a Bessemer converter in the presence of basic slags, supplyingadditional heat thereto to maintain an increased fluidity of the mass,and injecting into the mass divergent jets of gas to intimately mix themetal with the and injecting into the mass gas in divergent anddownwardly inclined jets to intimately mix the metal with the basic slagwhereby to completely eliminate the phosphorus, sulfur and otherimpurities from the mass.

10. A process for producing hard steel which consists in placing crudeiron in a Bessemer converter in the presence of basic slags,wsupplyingadditional heat thereto to maintain an increased fluidity of the mass,injecting gas into the mass in such manner as to intimately mix themetal withthe basic slag, and injecting gas into the converter over themass of metal in a more or less tangential direction whereby tocompletely eliminates the phosphorus,-sulfur and other impurities fromthe mass.

'11. In-the manufacture of steel in a Bessemer converter in the presenceof basic slags,

the process of intimately mixing the metal with the slags whichconsists-in introducing into the charge below the surface thereof gasunder pressure in such direction as to bring the metal and slags intoclose and thorough contact.

12. The process of producing hard steel containing a substantialproportion of carbon which consists in placing crude iron in a Bessemerconverter having a basic lining, in the presence of basic slags,supplying additional heat to the mass by an electric current, injectinginto the mass below its surface gas in such "manner as tointimately mixthe metal with the basic slag whereby to completely eleminate thephosphorus, sulfur and other impurities and excess of carbon in a singleoperation.

. 13. The method of producing hard steel containing a substantialproportion of carbon which conslsts in, placlng crude iron in a Bessemerconverter having a basic lining,

adding suflicient lime thereto to"transform the silicon, sulfur andphosphorus into silicate of lime, sulfid of lime and phosphate S V v oflime in the presence of basic slags, supplying additional heat to themass to in-, crease its fluidity, and injecting gas into the mass below,its surface in such manner as to produce an intimate mix'lngiofthe-metal and slag whereby to eliminate the silicon,

sulfur and phosphorus in the form of silicate of lime, sulfid of limeand phosphate of lime.

14. The method of producing hard steel containing a substantialproportion of carbon which consists in placing crude iron in a Bessemerconverter having a baslc llnlng,

'- adding suflicient lime thereto to transform the silicon, sulfur andphosphorus into silicate of lime, sulfid of lime and phosphate oflime,-placing an electrode in said converter, passing an electriccurrent .through said mass, thus supplying additional heat to increasethe fluidity of the mass, removing the 4 GEORGES CINILLE.

Witnesses:

HENRI LALANDE, ETIENNE GARRY.

